Changes proposed to Japanese decommissioning

A proposal to change decommissioning rules in Japan could mean that operators will contribute to funds only during operation, and not, as previously, for a decade after final shutdown.

The changes were proposed by a subcommittee of the country's Ministry of Economy, Trade and Industry on 19 October, according to a report by Atoms in Japan.

In common with most countries, Japan's nuclear operators build up a fund for decommissioning and disposal of radioactive waste by gradually putting money aside during the operating life of the reactor. In Japan this had been defined as the licensed operating period, which is nominally 40 years, plus ten further years.

METI's proposal would be to remove the additional ten years, so that funds have to have reached the appropriate level before the reactor is taken out of service.

While the change would simplify matters, it would also raise the rate of savings to decommission reactors later in their operating periods. On the other hand, it is easier for utilities to make decommissioning payments when a reactor is generating electricity and therefore income.

However, by 2020 decommissioning arrangements are set to change again with Japan's move to a liberalised electricity market. Under 2020 rules nuclear utilities will be free to decide their own schedule of meeting decommissioning costs.

Japan has 17 reactors that are already officially being decommissioned, including the four that were destroyed in the 2011 accident at Fukushima Daiichi and six which utilities have subsequently decided not to restart. A further 42 reactors are operable, of which 24 have applied to restart though only two are currently licensed and generating electricity.